Runner Bean is a promising crop for high-altitude areas of the tropics. Large influorescences (branched flower clusters) and edible beans are produced on rapidly climbing vines 3-4 m (10-13 ft) long, which, in the absence of freezes, are perennial, returning year after year from tuberous roots. Some varieties have a more shrub-like growth habit. Runner Beans are one of the most productive types of beans (900-1100 kg/ha dry beans in Kenya) in mild climates.
Runner Bean originated from from the highlands of Central America.
Runner Beans are well known for their showy (scarlet, white or mixed) flowers, which have ornamental value and can be added for color in salads. They are also cultivated for their immature pods, dried beans, starchy roots (see caution in section on cooking) or leaves. The dried beans are a good source of protein, minerals and essential amino acids (lysine in particular). Young, tender shoots/leaves can be added to other cooked vegetables or eaten fresh. The vines may also be used to feed livestock or allowed to grow as a cover crop.
- Elevation: 0 - 2,000 m (0 – 6,000 ft)
- Rainfall: Consistent throughout year (500 – 2000 mm [≈ 20-80 in]); susceptible to drought
- Soil Types: Well drained; wide range (light to medium textured is best) of soil types
- Temperature Range: 16-21° C (60-70° F); temps over 32°C (90° F) limit seed formation
- Day Length Sensitivity: variety dependent (domesticated forms usually short-day plants)
- Light: Full-sun Runner Beans are nitrogen-fixing and respond well to seed-innoculation with rhizobacteria. It is often planted with maize.
Though new plants will grow from tuberous roots, Runner Beans are normally propagated from seed planted after any chance of frost or before the rainy season. Plant seeds about 5 cm deep at an in-row spacing of 20-30 cm, with rows 1 m apart. Seeds germinate 10-14 days after sowing. Support climbing types with vertical poles, trellises, or other structures. Early-weeding helps with crop establishment; avoid deep hoeing, which can injure the roots.
Harvesting and Seed Production
Immature pod harvest starts 3 months after sowing (when pods are not yet thickened by the developing seeds); continuous picking helps maintain productivity over 2-3 months. Harvesting of dry beans (for consumption or seed saving), 4-5 months after sowing, occurs when the bean pods become dry and brown. Thresh or shell the pods to remove the seeds inside. Yields are higher with climbing than bush types.
Pests and Diseases
Aphids may attack the blossoms of Runner Beans. Soap or oil sprays are effective against aphids. Other common pests include snails and slugs, which attack bean seedlings before they begin to climb. Collecting snail and slugs by hand, or creating traps are effective ways to remove them. Poor bean set is often caused by lack of soil moisture or the absence of insect pollinators.
Cooking and Nutrition
Before eating, dried Runner Bean seeds should be cooked to break down antinutritional factors and phytohaemagglutinin (as with other beans, runner bean has small concentrations of this compound, which can be toxic if consumed in large amounts). The tuberous roots may also contain toxic compounds; these can be removed by cooking (discard the cooking water). Immature pods, harvested before the bean seeds have fully developed, can be prepared as other green beans or eaten raw. Flowers are eaten raw, or cooked.